Boiler



3 SHEETS-SHEET l.

R. W. BIRCHFIELD.

BOILER.

APPLICATION FILED IULY 30.1920.

Patented Oct. 18, 1921.

M m m n R. w. BIRCHFIELD.

BOILER.

AP'PLICATION HLED JULY 30, 1920.

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I, UNITED STATES* PATENT n oFFicE..

ROBERT W. BIRCHFIELD, or WAUKEGAN, irLnoIs.

BOILEB.

To all whom. it may concern:

Be it known that I, ROBERT W. BIRCH- FIELD, a citizenof'the United States, and a resident of Vaukegan, in the county 'df Lake and State of Illinois, have invented certain new and useful Improvements in a Boiler, of which the followingis a specification.

My invention .relates to improvementsA in boilers and has special reference to an improved boiler and boiler construction.

The objectof my invention is to provide asteam or hotwater boiler preferably constructed of steel plates and in the construction of -which` all rivets and calked joints except the flue ends, shall be eliminated; in which the skin wall or shell 'of the boiler shall be substantially a continuous lmetallic plate; which boiler shall be of the horizontal return flue type provided with water legs at the sides and ends of the tire box, and which shall be of relatively light weight, strong to resist internal pressure and easily built.

I accomplish my purpose by forming an` exterior sheet to provide substantially the upper half of the cylindrical part df theA boiler and the outer walls of the side water legs, and an inner main sheet which forms the lower part of the cylindrical shell and the inner walls of the side water legs. These two plates are joined together at their yedges by welding.

The boiler is completed by suitable end` plates joined to the two main plates by welding closing the ends of the boiler and forming front and rear water legs.

The simplicitymof the novel construction is made possible by the development of improved methods of welding the plates together. 0 proved means ofstaying the lnner and outer sheets of the water legs whereby I avoid all external joints 'which are not metalized or welded.

An important feature of my improvement resides in the novelmanner in which I form the connections `at the lower ends of the water legs, between the inner and outer sheets, viz: I yprovide a horizontally projecting iangepreferably 'on the inner 'sheets and projecting outwardly and I join the edge of this flange to the lower edge of the outer sheet by welding.

stantially to the middle of the cylindrical Specification of Letters Patent.

My invention also involves 1m,`

shell, then forward to form the roof of the auxiliary fire space, then down to form the flue sheet for the lower shorter iues, and this is `joined atits edges to the edges of the main inner sheet by welding.

Patented oet. 18, 1921.` I i Application led July 30, 1920. Serial No. 399,999.

The completed boiler consistsl of a hori'- zontally return iue boiler havingv the fire space or furnace completely inclosed in water legs" and every joint therein welded so that in eiect the whole boiler shell is a continuous integral sheet of steel.

Furthermore no longitudinal welded connection of the sheets isexposed tol the fire and themore important olf the welded joints are arranged at the external surface of the boiler where the fire cannot possibly reach them.

While I have, in the accompanying` drawings, forming part of this invention, illustrated a boiler of the horizontal return tube type constructed in accordance with my invention, it should be understood that al1 of the features of my invention are `not limited or coninedto this particular type of boiler but are capable of application to and embodiment in other types.

In said drawings Figure l is a vertical central longitudinal sectional view of the boiler; y

Fig. 2 is a vertical cross sectionfon the line 2 2 of Fig. l;

LFig. 3 is a vertical cross section on the line 3 '3 of Fig. l; and

Fig. 4 is a horizontal section on the line 44-0f Figa.

The boiler illustrated in said d-rawings has an upper horizontal cylindrical body portion 1 from which depends side water legs 2,

and forward and rear end water legs 3'and et respectively inclosing a fire space or furnace 5. The cylindrical body portion contains return iues 6 in its upper haltf which extend from end to end thereof and shorter flues 7 in its lower half which extend from 4the forward end of the boiler to a rear auxiliary iue sheet 8 arranged at the forward side of an auxiliary fire space 9 and through which the tire gases escape from the ffurnace space 5. The gases iowirorn the furnace space 5 through the auxiliary space 9 then through the shorter iues 7 to the forward end of the boiler where I provide a smoke box l0 connecting the upper and lower Hues and causing the gases to return through the upper iflues to the rear end of I providela main outer sheet 12 formed of`U- shape, the middle portionI forming the upper,

I cylindrical side 13 `of the body 1 andthe sides of fthe U extending down and forming the outer walls of the side water legs 2,- the inner wall of the boiler is formed of a second sheet 14 which is also formed into ageneral U-shape preferably with this distinction, however, that the bend of the U is reversed to form the lower part 15 of i the cylindrical body Aportion l of the boiler.

The sides of the inner U-shaped sheet 14 form the inner walls of the side water legs ing, as shown at 17. At the rear ypartof 2. For completing the side water legs at their lower ends I provide one of the main sheets, preferably the inner sheet 14 with horizontal outwardly extending flanges 16- at their lower edges which project outwardly to'contact with the lower edges of the outer seat, and I join the contacting edges by weldthe main inner sheet '14 the sidewalls ex-p tend up to about the middle line of the cylindrical part 1 of the boiler to form the sides ofthe auxiliary iire space 9.

The rear water leg 4 isbuilt up of a rear flue sheet 18 which is cut to conform to and contact with the rear edge of the outer main boiler sheet l2"and is provided inits upper part with suitable holes A19 for receiving the rear ends of the return flues 6. The

4edges of this outersheet are metallically joined te the rear edge of the outer sheet v 12 by welding, as shown at 20.

The inner wall of the rear water leg 4 1S` preferably formed of a sheet 21 which extends up'wardly from the lower edge ofthe rear water leg -to the to of the auxiliary furnace space 9 substantially parallel with the`- outer rear sheet' 18. The upper part of this inner sheet extendsforwardly toform the roof22 of the auxiliary lire space 9fand is theri'bent downwardly to form the ,said

l auxiliary rear flue` sheet 8. The edges of this inner sheet are metallically joined by welding as ,shown at` 23, to the adjacent edges of the inner main sheetv14.' The auxiliary ,rear luesheet 8 yis provided with suitfeo ,able openings for receiving the rear ends of the lower shorter tubes7r- The lower edges of the rear sheet 18 and 21 are joined together to close the vlower end of the rear Vwater leg,- the inner sheet being provided with a horizontal outwardly extendingflangev 24 which is; metallically shown at 29.

.stays 39 within the ,Y these strap stays to. the

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joined at its outer edge` to the lower edge of the outer sheet by welding, as shown at 25.

The forward -waten leg 3 is constructed similarly to the'rear water leg 4. I provide an outer front-l sheet 26 which is cutto fit within the forward. edge of the outer U- shaped sheet 12 and ismetallically joined` Athereto by welding as shown at 27. I also provide an inner. front sheet 28fwhich is cut to conform with the transverse shape of the inner main sheet 14, and is metallically united therewith at its edge by' welding als To provide alire door opening 30, I ref,- erably form a forwardlyprojecting fange 31 integral with the inner sheet and defining said opening and welded at its lforward edge. to the outer'sheetat the" edge of a similar opening therein. Y

As with the other water legs, A

ably close the. front water leg 3 at 'its lower end by means'of aflange- 32 projecting for- I preferwardly from the inner` sheet into lcontact 'with the lower edge of the outer. sheet and metallically shown at 33. i

For 'the purpose of strengthening the sev,

joined thereto by welding as eral water legs so-thatthey will properly v withstand the pressure to which the boiler 1s subjected in use, I connect the inner and outer sheets in each water leg, by means of a plurality of stay bolts 34. v

In order to avoid any exposed calked or unmetallized'joints between the stay bolts and the severalsheets I provideythreaded sockets 35 Welded to the inner side oftheinner sheets and adapted to receive the inner threaded ends 36 of the stay bolts 34.

The bolts project through alined openings 37 in the outer sheets, their outer ends being preferably substantially .flush with ,n the outer surfaces of the outer sheets.- I

make the openings '371 countersunk and larger at the outer sides of the outer sheets so as to facilitate the welding of the outer' ends of the bolts to the outer sheets as indicated at 38.

Tol strengthen the cylindrical` body portion 1 of theboiler I provide a plurality of boiler 4.and connecting theinner sheet 14 to the outer sheet 12. f

These stays aregarran'giid across the 'side water legs and form substantial continuations of the cylindrical shell formed, of the Ujfportions of the two sheets'12-and 14'.` I provide enough of these.-stays toyretain the cylindrical `body portion 1 intl-ue shape as against the internal their endsthereto.

'a boiler suitable-for power vandv heatin pur'- pressure and AI connect...

,sheets by welding' j It will -now be evident that by'- ineaus off-'f my improvements I am enabled to piv'ovide- .poses which has a substantially contlnuousA i I o uter shell which is homogeneous and which v 1.30

' throughout; also by means of my improvement I eliminate all double thickness joints,

all riveted and calked joints and that the outer skin orf shell of the boiler is to all 'practical intents and purposes an integral shell. Furthermore, the cylindrical part of the boiler has no longitudinal seams either at the lower or the upper side.

As many modiications of my invention will readily suggest themselves to oneskilled in the art, I do not limit or confine my invention to the specic'structures or the specific sequence of steps herein shown and described.

I claim:

1. In a boiler of the kind described, in

, combinationfan outer shell, flues therein,

and croivn and side sheets, the fire box between said side sheets including a main combustion space and anl auxiliary combustion lspace rising above one end of the main com bustion space, the sheets at .the sides of said main and auxiliary combustion spaces. to-y gether with the main crown sheet being formed from a vsingle plate, and a single plate forming the back sheet, the crown sheet for the auxiliary combustion space and the iiue sheet adjacentthereto.

2. In a boiler'of the return-flue type and a combined re box, in combination. an outer shell, iues therein, crown and side sheets, the fire box between said side sheets including a main combustion space and an auxiliary combustion space rising above the main combustion space, the sheets at the sides of said main and auxiliary combustion and an auxiliary' combustion space rising spaces together with the main crown sheet, being formed from asingle plate, and a single plate forming the-back sheet the crown sheet for the auxiliary combustion space and the iue sheet adjacentA thereto, 'the joined edges being united by welding.

3. In a boiler of the return-flue type, and a combined fire box, 4flues therein and crown and side-sheets, the fire box between the side sheets including a main combustion space above the main combustion space, the sheets at the sides of the combustion spaces and the crown sheet of the main. combustion space being made ofa single plate, and a tively long radius and the two plates being joined at their adjacent edges. 4:. In a boiler of the kind described,in combination, an outer shell, lues therein, and

the rear end of the fire box joined to the lrear edges `of said single plate, said closure including the back sheet, the crown `sheet of the auxiliary combustion space, and the adjacentflue sheet.

5. In a boiler of the ret-urn lue type having a cylindrical body and depending water legs inclosing a fire-box, in combination, an outer shell, lues therein, and crown and side sheets, the fire box between said side sheets` including -a main combustion space and an end of the main combustion space, the crown sheet being concave and formed substantially on the radius of the cylindrical body, the sheets at the sides of said4V main andy auxiliary combustion spaces together with the crown sheet being formed from a single plate, and a sheet metal closure for the rear end of the fire box joined to the rear edges of said single plate, said closure including the back sheet, the crown sheet of the auxiliary combustion space, and the adjacent flue sheet.

6. In a boiler of the kind described, in combination, an outer shell, flues therein, and crown and side sheets, the fire box between said side sheets including a. main combustion space and an auxiliary combustion space rising above one end of the main combustion space, the sheets at the-sides of said main and auxiliary combustion spaces together with the main crown. sheet being formed from a single plate, and a metal sheet closure for the rear end of the lire box joined to the rear edges of said single plate by welding, said closure including thel back sheet, the crown sheet of the auxiliary combustion space, and the adjacent flue. sheet.

Signed at Chicago, Ill., this 28th day of July, 1920.

ROBERT w. BIRCHFIELD.

auxiliary combustion space rising above one 

